Automobile radio antenna



Feb. 7, 1939. M. F.- sHEA Er AL AUTOMOBILE RADIO ANTENNA Filed June 17, 1937 Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE AUTOMOBILE RADIO ANTENNA of Delaware Application June 17, 1937, Serial No. 148,770

4 Claims.

This invention relates to vehicle radio antennae and, more particularly, to a novel radio antenna for use on automobiles or like vehicles in conjunction with radio receiving sets.

One object of the invention is to provide a novel antenna for use on the present day automobile having an all-metal top, and which eliminates the objectionable characteristics of prior antennae of the same general class.

A more specific object of the invention is to provide a novel adjustable antenna which is adapted to be mounted on an automobile within reach of the operator and in close proximity to the usual radio set, so that the operator may adjust the length of the antenna for the reception of signals of different strengths while the automobile is in motion, and by means of which location of the antenna it is possible to use a short lead-in conductor to the set, thus reducing 20 pick-up of disturbances.

Another object of the invention is to provide a novel antenna which is adapted to be mounted at a location on an automobile where it will be least aiected by various disturbances such as engine noises, tire static, etc.

Still another object of the invention is to provide a novel antenna which may be easily mounted on an automobile by drilling two holes in a part of the vehicle automobile body where the drilling Aof holes is unobjectionable.

A further object of the invention is to provide a novel telescopically adjustable antenna having novel mounting means whereby the antenna may be securely clamped and good electrical connection may be made to it in a very simple manner.

Other objects and features of the invention will appear hereinafter.

In the accompanying drawing:

Fig. 1 is a perspective view illustrating the mounting of the antenna on an automobile body, the antenna being shown in collapsed or contracted condition;

Fig. 2 is a similar View showing the antenna in its extended condition;

Fig. 3 is a. fragmentary perspective view of the lower part of the antenna showing the supports more clearly;

Fig. 4 is a sectional view of one of the mounting supports for the antenna;

Fig. 5 is a similar view of the other mounting support; and

Figs. 6 and 7 are perspective views of the parts of the yoke or clamp which is employed to hold the antenna rod securely and to make good electrical connection thereto.

Prior to the advent of the all-metal top ernployed on the present day automobile, it was the practice to employ a radio antenna mounted in the top of an automobile and usually comprising a wire mesh or screen mounted beneath the fabric top covering of the automobile. Such an antenna has been known to be very eflicient and quite satisfactory. With the advent of the allmetal automobile top, however, it became necessary to resort to other forms of radio antenna for automobiles and like vehicles. Various forms of antenna have been employed on automobiles having all-metal tops but each of them has been subject to some serious objection.

One type of antenna which has been employed is the so-called undercar or undercarriage antenna. This type of antenna has not been satisfactory from either a mechanical or electrical standpoint. It is subject to mechanical damage due to obstructions on the road and very frequently such an antena has been damaged or even torn from its supports. From an electrical standpoint, such an antenna is relatively inefcient due to the necessity of mounting it close to the under part of the automobile body where it is electrically shielded to at least some degree by the automobile body. Furthermore, such an antenna is subject to static electrical disturbances caused by the tires of the automobile while it is in motion. Such disturbance is very annoying and is very difficult to eliminate. In fact, it reaches such proportions at times that the radio set is rendered substantially inoperative. An antenna of this type is further objectionable in that its efiiciency is greatly reduced by snow, ice and dirt which accumulate on it from the road bed. Furthermore, in the Winter time, sodium chloride and other melting agents which are employed on roads cause serious depreciation in the eiciency of an antenna of this type.

Another type of antenna which has been employed on automobiles having all-metal tops is that which is mounted on the top of an automobile externally to the automobile body. Whilel such an antenna is fairly eiiicient electrically, it is difficult to install and it requires the drilling of holes in the metal top of the automobile. This is objectionable because it is apt to cause leaks in the automobile top. Furthermore, an antenna of this type is very conspicuous and many persons object to its appearance. A further objecltion to such an antenna is that it requires a long lead-in conductor from the antenna to the radio set which must be properly shielded to prevent pick-up of electrical disturbances, particularly from the ignition system oi the auto mobile. This necessary shielding of the long leadin conductor causes a material decrease in the strength of the signal, thus reducing the overall eiciency of the antenna system.

In accordance with the present invention, there is provided an adjustable antenna which is adapted to be mounted on the body of an automobile as illustrated in Figs. 1 and 2 of the drawing. As shown in these figures, the antenna l is adapted to be mounted on the side of the cowl 2 of the automobile body 3. The antenna comprises an adjustable antenna rod carried by two insulators or supports 5 and 6. The antenna rod comprises a main section 'l which is carried by the supports, and one or more telescopically adjustable sections carried by the stationary section, in the present instance there being illustrated two telescopically adjustable sections 8 and 9. It will be understood, therefore, that the sections 1 and 8 are hollow to provide the telescopic structure.

In its collapsed or contracted condition, as shown in Fig. l, the antenna rod is of short length and is inconspicuous. By virtue of its location, the antenna rod is within easy reach of the operator of the vehicle who may adjust the antenna rod to any desired length while the car is in motion by simply reaching out of the front window. The more the antenna rod is extended, the greater will be the strength of the signal which the antenna picks up and supplies to the radio set. When the automobile is traveling within close range of the broadcasting station, for example, when traveling through cities or in the vicinity thereof, the antenna rod may be collapsed or contracted, in which condition it is inconspicuous. When the automobile is traveling at a distance from the broadcasting station, however, the antenna rod may be extended to any desired length to obtain the required increase in its eiciency to receive the broadcast signals. Thus, the antenna is adjustable according to the strength of the signal which it is desired to receive and, since it will usually be collapsed or contracted while traveling through populated areas, it is inconspicuous and unnoticeable to passersby.

As may be seen in Figs. 1 and 2, the antenna is located close to the radio set I0 which is usually mounted on the dashboard of the automobile in the approximate position shown. It is possible, therefore, to use a short lead-in conductor Il which may be easily shielded without materially reducing the efficiency of the antenna system. The use of a short lead-in conductor of this character greatly reduces the pick-up of disturbances. It will be noted also that the antenna is suiliciently removed from the engine and the tires of the automobile so that it is substantially unaffected by disturbances from these sources. Moreover, it is free from damage or the effects of deleterious agents to which the under-car antenna is subjected, as pointed out above. Further experimental results show that the shielding effect of the car on the antenna is less in the antenna of the invention than in the case of the under-car, screen, or over-head types of antennae, other things being equal, and the efficiency of the antenna of the invention is correspondingly higher.

Referring now to Fig. 4, the upper support 5 for the antenna rod comprises a hollow knob i2 which is formed of insulating material, such as Bakelite. Adjacent the outer end of the knob, there is provided a transverse opening through aisance which the antenna rod extends. The base of the knob seats on a resilient ring I3 formed o! insulating material as rubber. The ring I2 rests against the outer surface of the cowl 2. An insulating clamping piece I l. which may be formed of Bakelite, engages the inner surface of the cowl 2 and has a central portion I5 which extends through the ring I3 and into the central part of the knob 5.

Within the knob 5, there is provided a yoke or clamp I6 which comprises a metallic strap I1 shown in Fig. '7 and a nut i8 shown in Fig. 6. The ends of strap l1 are bent inwardly as shown at I9 and are apertured to receive an annular extension 20 on the nut I8 when the nut is placed within the strap. The inner walls 2l of the hollow knob 5 prevent the nut from turning. The strap il extends around the antenna rod and serves as a clamp therefor. A screw 22 extends through the clamping piece I 4 and threadedly engages the nut I8. When the screw 22 is tightened, the antenna rod is tightly clamped by the strap Il and, at the same time, the supporting knob 5 is securely attached to the cowl wall. Furthermore, the strap Il makes good electrical contact with the antenna.

The screw 22 is provided with a non-circular head 23 by means of which the screw may be tightened, using a wrench or like tool. The end of the head 23 is provided with a threadedrecess which receives a small screw 24 by means of which the lead-in conductor I I may be connected to the screw 22. Thus, the screw head 23 serves as a terminal post for the lead-in conductor. The lead-in conductor may have its shield 25 electrically connected to the cowl wall by means of a connection 26 so as to ground the end of the cori-a ductor shield.

The lower support 6 is similarly constructed but in this instance, the hollow knob is provided with a transverse opening which extends only partly through the end portion of the knob so as to seat the lower end of the antenna rod as clearly illustrated, and there is provided a small opening 2l which serves to drain off any water which may i'lnd its way into the hollow antenna rod structure. Furthermore in this instance, a diierent type of screw 28 is employed in place of the screw 22, since the only purpose of the screw in this instance is to secure the antenna rod mechanically. The outer end of the screw extends through an opening in the antenna rod as shown at 29 and thus serves to lock the antenna rod in place and prevents rotary movement thereof. Aside from these differences, the lower supporting structure is similar to the upper support.

In order to mount the antenna, it is simply necessary to drill the two necessary holes in the cowl wall of the automobile and then assemble the two supports in the manner which will be obvious from the above description. Each mounting support requires the tightening of a single screw. The location of the antenna is such that the mounting may be easily accomplished with very little eiort. The location of the antenna also has the various other advantages above enumerated.

It will be understood, of course, that the invention is not limited to the specific form illustrated on the drawing and that various modifications, particularly in the details of the mounting of the antenna rod, may be resorted to without departing from the scope of the invention.

We claim:

1. A vehicle radio antenna structure adapted 1L to be mounted on a substantially vertical vehicle wall, comprising an antenna rod, and a pair of spaced superposed supports for mounting said rod in substantially vertical position on said wall, each of said supports comprising a knob-like insulating member adapted to seat against the outer surface of said wall with its axis perpendicular to the wall, the lower insulating member having a socket-like recess extending transversely of the axis of the insulating member for receiving and seating the lower end of said rod and an axial bore opening communicating with said recess, the upper insulating member having an opening extending transversely of the axis of the insulating member through which the antenna rod extends and an axial bore opening communicating with said transverse opening, a rod-engaging member within each of said insulating members, and a fastening element extending from each said rod-engaging member through the axial bore opening of the associated insulating member and through the said wall.

2. A vehicle radio antenna structure adapted to be mounted on a substantially vertical vehicle wall, comprising an antenna rod, and a pair of spaced superposed supports for mounting said rod in substantially vertical position on said wall, each of said supports comprising inner and outer axiallyaligned insulating members disposed on an opening in the said wall, the outer member o! the lower support having a vertical recess at a substantial distance from said wall for receiving and seating the lower end of said rod, the outer member of the upper support having a vertical opening aligned with said recess through which said rod extends, a metallic rod-engaging member within each of said outer members, and a metallic fastening element extending from each said rod-engaging member through the axial bore openings of the associated outer and inner members and through the said extension of one member, whereby the exposed metallic portions of said structure are spaced substantially from said wall and the internal portions are effectively insulated from the wall, so that the electrical capacity between the wall and said portions is substantially minimized.

3. A vehicle radio antenna structure adapted to be mounted on a substantially vertical vehicle wall, comprising an antenna rod, and a pair of spaced superposed supports for mounting said rod in substantially vertical position on said wall, each of said supports comprising inner and outer axially-aligned insulating members disposed on the inner and outer sides respectively of said wall and each extending for a substantial distance from said wall, and a resilient ring for seating the outer member on the outside of said wall, the said inner and outer members of each support having axially-aligned bore openings and the inner member having an axial extension within an opening in the said wall, the outer member of the lower support having a vertical recess at a substantial distance from said wall for receiving and seating the lower end of said rod, the outer member of the upper support having a vertical opening aligned with said recess through which said rod extends, a metallic rodengaging member within each of said outer members, and a metallic fastening element extending from each said rod-engaging member through the axial bore openings oi the associated outer and inner members and through the said extension of one member, whereby the exposed metallic portions of said structure are spaced substantially from said wall and the internal portions are effectively insulated from the wall, so that the electrical capacity between the wall and said portions is substantially minimized.

4. A vehicle radio antenna structure adapted to be mounted on a substantially vertical vehicle wall, comprising an antenna rod, and a pair of spaced superposed supports for mounting said rod in substantially vertical position on said wall, each of said supports comprising inner and outer axially-aligned insulating members disposed on the inner and outer sides respectively of said wall and each extending for a substantial distance from said wall, and a resilient ring for seating the outer member on the outside of said wall, the said inner and outer members of each support having axially-aligned bore openings and the inner member having an axial extension within an opening in the said wall. the outer member of the lower support having a vertical recess at a substantial distance from said wall for receiving and seating the lower end of said rod, the outer member of the upper support having a vertical opening aligned with said recess through which .said rod extends, a metallic yoke within each oi' said outer members for holding said rod, a nut carried by each yoke, and a metallic screw shank extending through the axial bore openings of the aligned members and threadedly engaging said nut, whereby the exposed metallic portions of said structure are spaced substantially from said wall and the internal portions are eiectlvely insulated from the wall, so that the electrical capacity between the wall and said portions is substantially minimized.

EDWINA. 

